Induction heat seal liner and method of manufacture

ABSTRACT

Induction heat-seal liner that allows a visual inspection of the product in the container to be made through the seal, and/or an aroma from the product to be detected through the seal, while the seal remains secured to the container to protect against leakage or contamination. In one embodiment, the liner has an intermediate metal-foil layer having a central opening, and a central liner portion, aligned in a thickness direction with a central opening of a metal-foil layer, comprises one or more materials or spaces that provide visibility into and/or aroma penetration from the open mouth of the container. In another embodiment, a dual heat-seal liner having a dispensing aperture is provided that heat seal bonds to both the cap and container to form a non-removable closure assembly that protects the metal-foil layer from degradation by the product being dispensed.

FIELD OF THE INVENTION

The present invention relates to induction heat-seal liners for sealingthe mouth of a container and a method of manufacture. In one embodiment,a heat-seal liner allows an aroma of a product in the container topermeate the seal, and/or allows visual detection of the product, whilemaintaining the barrier properties of the seal and preventing leakage ofthe substance from the container. In another embodiment, a dualheat-seal liner having a dispensing aperture is provided that heat sealbonds to both the cap and container to form a non-removable closureassembly that protects the metal-foil layer from degradation by theproduct being dispensed.

BACKGROUND OF THE INVENTION

Seals have been used on containers for many years, to prevent leakage orcontamination of the substance within the container and to increase theshelf life of the product. For example, seals are used on containers forcosmetics, foods, drinks, medicines and other items in the form ofcreams, gels, powders, or liquids. Seals used for this purpose aretypically placed over the opening of the container or, in someinstances, within the cap on the container.

However, consumers often want to smell items having a fragrance oraroma, such as lotions, creams, body washes, shampoos, deodorants,perfumes, laundry detergents, air fresheners, coffee and spices, beforepurchasing the items. As a result, many products are sold today withoutseals because there is no commercially viable seal on the market thatallows consumers to smell the scent of the product within the container.Specifically, prior art seals are essentially hermetic seals intended toprevent leakage of the product from the container and to limit air flowinto and out of the container to preserve the product and maximize theproduct's shelf life. In so doing, they trap the scent or aroma of theproduct within the container.

As a result, scented products are often sold in containers withoutseals, so that consumers can remove the cap and smell the scent prior topurchase. The fact that many scented products are still sold incontainers without seals today is evidence that the prior art seals donot allow adequate scent permeation and prevent leakage in a costeffective manner.

The absence of a seal increases the possibility of spillage duringtransportation and the chances that a product may be tampered with ortainted prior to sale to the consumer. It is not uncommon for consumersto go beyond simply removing the cap and smelling the item, by actuallyapplying some of the product onto their body to sample the product andits fragrance. In so doing, the consumer may stick their fingers intothe substance or on the opening where the substance comes out.Oftentimes, after sampling the product, the consumer closes the cap andreturns the container to the shelf in the store.

This sampling of the product causes several problems. From theconsumer's perspective, by placing their fingers into the substanceand/or coming in contact with the opening where the substance comes out,the sampler may be contaminating the substance and spreadinggerms/bacteria. Additionally, each time a consumer samples the productand then returns it to the shelf, the volume of the substance within thecontainer decreases. As a result, the consumer that eventually purchasesthe product is unknowingly purchasing less than a full container of aproduct that may have been contaminated and/or contain germs/bacteria.

From the retailer's perspective, consumers that sample products and thenreturn them to the shelf sometimes do not place the cap on tightly,which may result in spillage if the container is tilted or falls on itsside. Additionally, the shelf life of the substance within the containermay be reduced or altered by the absence of a seal on the container orhaving been opened and exposed to the surrounding environmentalconditions by a sampling consumer prior to sale. Also, the absence of aseal on a container may result in the substance contacting and/oraccumulating within the cap on the container, which may cause spillagewhen the cap is removed and a less appealing presentation to theconsumer. These situations may result in the retailer being unable tosell the product or generating product returns or charge-backs, whichmay have an adverse effect on the retailer's, product manufacturer's ordistributor's reputation and financial performance. Additionally, theretailer, manufacturer and/or distributor may incur liability if aconsumer is harmed by the contaminated product.

SUMMARY OF THE INVENTION

In one embodiment of the invention, an induction heat-seal liner isprovided that allows a scent or aroma from a product to be detectedthrough the seal, and/or allows a visual inspection of the product to bemade through the seal, while the seal remains secured to the container.In another embodiment, a dual heat-seal liner having a dispensingaperture is provided that heat seal bonds to both the cap and containerto form a non-removable closure assembly that protects the metal-foillayer from degradation by the product being dispensed.

In one embodiment of the invention, an induction heat-seal liner isprovided comprising:

a top closure-facing layer, a bottom heat-seal bonding layer, and anintermediate metal-foil layer disposed in a thickness direction betweenthe top and bottom layers,

the top, bottom and intermediate layers being bonded to form an integralinduction heat-seal liner,

the metal-foil layer having a central opening surrounded by a metal-foilportion configured to lie above a container rim surrounding an openmouth of a container body, and the bottom layer having a heat-sealbonding area configured to lie above the container rim that is activatedby heating of the metal-foil portion to induction heat-seal the bondingarea to the container rim.

In one embodiment,

the liner has a central portion, aligned in the thickness direction withthe central opening of the metal-foil layer, comprising one or morematerials or spaces that provide visibility into and/or aromapenetration from the open mouth of the container, allowing visibledetection of and/or aroma detection of a product in the container body.

In one embodiment,

one or both of the top and bottom layers fills or partially fills thecentral opening of the metal-foil layer.

In one embodiment,

the integral liner comprises an adhesive, extrusion or thermallylaminated body.

In one embodiment,

the liner is an adhesive laminated body and includes adhesive betweenone or more of the top, intermediate and bottom layers, and the adhesivefills or partially fills the central opening of the metal-foil layer.

In one embodiment,

the central liner portion is clear or translucent to permit visibledetection of the product in the container body.

In one embodiment, a method of forming the liner comprises:

a) providing the metal-foil layer having the central opening; andsubsequently

b) laminating the metal-foil layer between the top and bottom layers toform the integral liner.

In one embodiment,

the laminating step comprises adhesive laminating the metal-foil layerbetween the top and bottom layers.

In one embodiment,

during the laminating step adhesive layers fills or partially fills thecentral opening of the metal-foil layer.

In one embodiment,

the providing step includes providing a support layer having a centralopening, and

the laminating step includes disposing the metal-foil layer and thesupport layer with their central openings aligned between the top andbottom layers to form the integral liner.

In one embodiment,

the providing step includes providing a sheet comprising the metal-foillayer and a sheet comprising the support layer, and forming the centralopenings through both sheets simultaneously.

In one embodiment, the method of forming the liner comprises:

a) providing top, intermediate and bottom sheets for forming the top,intermediate and bottom layers respectively;

b) laminating the sheets together to form a laminated composite sheetwith the intermediate sheet laminated between the top and bottom sheets;and

c) forming individual liners from the laminated composite sheet bycutting through the composite sheet in a thickness direction.

In one embodiment, the central opening in the metal foil layer is formedprior to the laminating step.

In one embodiment, during the laminating step the central opening iswholly or partially filled in.

In one embodiment, the method is a sequential in-line method includingsteps of:

prior to the laminating step, forming the central openings for aplurality of liners in the intermediate sheet;

the laminating step comprises feeding the sheets through one or moreroller pairs for laminating the sheets together to from the laminatedcomposite sheet;

the forming step comprises cutting through the laminated composite sheetin the thickness direction to form the plurality of liners.

In one embodiment, the steps of forming the central openings and cuttingto form the individual liners each comprise hole punching.

In one embodiment, the central opening and individual liner are formedsimultaneously.

According to another embodiment of the invention, a dual inductionheat-seal liner is provided comprising:

a top closure-facing heat-seal bonding layer, a bottom heat-seal bondinglayer, and an intermediate metal-foil layer disposed in a thicknessdirection between the top and bottom layers,

the top, bottom and intermediate layers being bonded to form an integraldual induction heat-seal liner,

the metal-foil layer having a central opening surrounded by a metal-foilportion configured to lie above a container rim surrounding an openmouth of a container body, and the bottom layer having a heat-sealbonding area configured to lie above the container rim that is activatedby heating of the metal-foil portion to induction heat-seal the bottomlayer bonding area to the container rim,

the liner having a central through-hole aligned in the thicknessdirection and extending through the central opening of the metal-foillayer and though the top and bottom layers,

the top closure-facing layer having a heat-seal bonding area toinduction heat-seal the top layer bonding area to an inner surface of aclosure, thus heat-seal bonding the liner to both the container rim andthe closure inner surface, while allowing a product to be dispensedthrough the open mouth of the container, the central through-hole of theliner, and out of a dispensing aperture of the closure.

In one embodiment,

one or both of the top and bottom layers partially fills the centralopening of the metal-foil layer to form a perimeter of thecentral-though hole that prevents contact between the product and themetal-foil layer.

In one embodiment,

the integral liner comprises an adhesive, extrusion or thermallylaminated body.

In one embodiment,

the liner has a circular or a multi-sided perimeter.

In one embodiment,

the liner is an adhesive laminated body and includes adhesive betweenone or more of the top, intermediate and bottom layers, and the adhesivepartially fills the central opening of the metal-foil layer to form aperimeter of the central though-hole that prevents contact between theproduct and the metal-foil layer.

In one embodiment, a method of forming the liner is provided comprising:

a) providing the metal-foil layer having the central opening; andsubsequently

b) laminating the metal-foil layer between the top and bottom layers toform the integral liner.

In one embodiment,

the laminating step comprises adhesive laminating the metal-foil layerbetween the top and bottom layers.

In one embodiment,

during the laminating step adhesive partially fills the central openingof the metal-foil layer to form a perimeter of the central though-holethat prevents contact between the product and the metal-foil layer.

In one embodiment,

the providing step includes providing a support layer having a centralopening, and

the laminating step includes disposing the metal-foil layer and thesupport layer with their central openings aligned between the top andbottom layers to form the integral liner.

In one embodiment,

the providing step includes providing a sheet comprising the metal-foillayer and a sheet comprising the support layer, and forming the centralopenings through both sheets simultaneously.

In one embodiment, a method of forming the dual induction heat-sealliner is provided comprising:

a) providing top, intermediate and bottom sheets for forming the top,intermediate and bottom layers respectively;

b) laminating the sheets together to form a laminated composite sheetwith the intermediate sheet laminated between the top and bottom sheets;and

c) forming individual liners from the laminated composite sheet bycutting through the composite sheet in a thickness direction.

In one embodiment, the central opening in the metal foil-layer is formedprior to the laminating step.

In one embodiment, during the laminating step the central opening ispartially filled to form a perimeter of the central though-hole thatprevents contact between the product and the metal-foil layer.

In one embodiment, the method is a sequential in-line method includingsteps of:

prior to the laminating step, forming the central openings for aplurality of liners in the intermediate sheet;

the laminating step comprises feeding the sheets through one or moreroller pairs for laminating the sheets together to from the laminatedcomposite sheet;

the forming step comprises cutting through the laminated composite sheetin the thickness direction to form the plurality of liners.

In one embodiment, the steps of forming the central openings and cuttingto form the individual liners each comprise hole punching.

In one embodiment, the central through-holes and individual liners areformed simultaneously.

In one embodiment, the method includes subsequent to forming the centralopenings, forming the through-holes, followed by forming the liners.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further advantages and features of various embodiments ofthe invention will be understood by referring to the followingdescription in conjunction with the accompanying drawings in which:

FIG. 1 is an exploded perspective view of an induction heat-seal linerpositioned between a cap and container rim according to one embodimentof the invention, the liner components being shown as separate layers ofa multi-layer structure prior to lamination to form an integral liner;

FIG. 2 is an exploded perspective view similar to FIG. 1 but showing theintegral liner after lamination;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged fragmentary perspective view, partially brokenaway, of the liner of FIG. 2 sealed to the container rim and with thecap removed, allowing the consumer to view and/or detect an aroma of theproduct through the liner;

FIGS. 5A-5B are schematic views of a method of making the liner of FIGS.1-4 from three component sheets, FIG. 5A showing an intermediate layersheet being first hole punched (to form central openings in theintermediate metal-foil layer), followed by the three sheets (top,hole-punched intermediate and bottom) being sent through the nip of apair of rotating rollers for forming a laminated web, and FIG. 5Bshowing a subsequent step of hole punching through all layers of thelaminated web to form individual liners;

FIG. 6 is an exploded perspective view of an alternative linerembodiment similar to that of FIGS. 1-4, showing the separate layercomponents again positioned between a cap and container rim, thisembodiment including an additional support layer having a centralopening;

FIG. 7 is an enlarged fragmentary perspective view, partially brokenaway, of an alternative embodiment of a liner for forming anon-removable cap, liner and container assembly, showing the linerheat-seal bonded to the container rim (without the cap);

FIG. 8 is a cross-sectional view of the assembled cap, liner andcontainer assembly of FIG. 7, showing the liner heat-seal bonded to boththe inner top wall of the cap (above the liner) and the container rim(below the liner) to form a non-removable closure assembly;

FIG. 9A is a schematic view of one method of making the liner of FIGS.7-8, showing three component layer sheets (top, intermediate and bottom)wherein the (metal foil) intermediate sheet is first hole punched(initial hole punch) to form central openings in the metal foil,followed by all three sheets being sent through the nip of a pair ofrotating rollers for forming a laminated web, followed by common holepunching (by liner ID hole punch) through all three layers of thelaminated web to form the common opening (liner ID), and followed by athird hole punching (by liner OD hole punch) to form individual liners;FIG. 9B is an alternative method of making the liner of FIGS. 7-8,similar to that of FIG. 9A but wherein the second and third hole punchesof FIG. 9A, are combined into a single hole punch for forming both theliner OD and ID simultaneously; and

FIG. 10A is a top perspective view of an alternative liner embodiment,similar to that of FIGS. 1-4, but configured for a generallyrectangular-shaped container, liner and cap; and FIG. 10B is a topperspective view of the liner of FIG. 10A.

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1-4 illustrate one embodiment of an induction heat-seal liner 10according to one embodiment of the invention. FIG. 1 shows the linercomponents as multiple layers, prior to lamination to form the integralliner 10 shown in FIGS. 2-4. The liner 10 includes:

a top closure-facing layer 20, a bottom heat-seal bonding layer 30, andan intermediate metal-foil layer 40 disposed in a thickness direction(TD) between the top and bottom layers,

the top, bottom and intermediate layers being bonded to form an integralinduction heat-seal liner 10,

the metal-foil layer 40 having a central opening 42 surrounded by acontinuous metal-foil portion 44 configured to lie above a container rim82 surrounding an open mouth 84 of a container body 86, and the bottomlayer 30 having a heat-seal bonding area 32 configured to lie above thecontainer rim 82 that is activated by heating of the continuous portion44 to heat-seal bond the bottom layer 30 to the container rim 82.

As shown in FIG. 1, the multiple component layers of the unassembledliner include in serial order from top to bottom: top layer 20;intermediate metal-foil layer 40; and bottom layer 30, the bottom layerincluding an upper layer 34 and a lower heat-seal bonding layer 31. Thelayers 20, 40, 30 (34 and 31) are shown stacked in a thickness directionTD aligned with a central vertical axis CA of the container body 86 andclosure cap 60. In this embodiment the container mouth has an annularrim 82, lying between a rim inner circumferential diameter RID and a rimouter circumferential diameter ROD, with the liner 10 having a matchingliner outer circumferential diameter LOD equal to ROD of the containerrim. The liner outer diameter LOD can be equal to or greater than therim outer diameter ROD.

In various embodiments, the top, intermediate and bottom componentlayers 20, 40, 30 may each comprise a single layer, or multiple layers;they may include adhesive layers for adhesively laminating the layerstogether to form the integral liner 10, as described hereinafter(adhesive layers A shown in FIGS. 3-4).

As shown in FIG. 3, the liner is configured to lie between the annularcontainer rim 82 and an inner top wall 62 of the cap 60, in order toseal an open mouth 84 of the container 80. The lower heat-seal bondinglayer 31 has a continuous peripheral portion 32 that lies over and isheat-seal bonded to the rim 82, the bonding being activated by inductionheating of the metal-foil portion 44 that in turn heats the bondingportion 32.

The cap 60 is sized to cover the open mouth 84 of the container 80; thecap includes a cylindrical top wall 61 having a peripheral sidewall 64extending downwardly from the outer periphery of the top wall 61. Theinner surface 6415 of the cap sidewall, and the outer surface 840S ofthe container mouth, include complimentary threads 64THR and 84THR thatare disposed in a radial space RS between 64IS and 84OS. In use, theliner 10 is disposed in the cap 60 adjacent the inner top wall 62, andthe cap is then twisted down onto the container rim 82 by threadablyengaging 64THR and 84THR to secure the liner between the cap inner wall62 and the container rim 82. The sealed container 80 can be readilyopened (e.g. by the consumer) by untwisting the cap (in the oppositedirection) to unthread 64THR and 84THR, allowing the consumer to removethe cap and then remove the heat-seal liner 10 by peeling the liner fromthe rim (this later step may be aided by providing a pull tab (e.g., 314as shown in FIG. 10) on the liner to facilitate grasping the liner andpulling it away from the container rim).

The liner of the present embodiment provides a number of advantageousfeatures that will now be described. One feature of the liner is toprovide the metal-foil layer 40 with a central opening 42 (a throughhole in the thickness direction TD); this positions the peripheralmetal-foil area 44 (surrounding the central opening 42) where it is mostuseful for induction heating, i.e., over the container rim, and reducesthe amount of metal foil material required. The central opening 42 inthe foil also enables the liner to be see-through, wherein the user canview (visually detect) the contents (product P) in the sealed container,without removing the heat-seal liner 10 from the container rim 82 (asshown in FIG. 4). This may be advantageous for sale or display purposes,e.g., allowing a visual inspection of the product prior to purchase,without removal of the seal (and avoiding contamination of the productby a prospective purchaser). To provide this feature, the other layersof the liner (i.e., top and bottom layers 20 and 30) of the liner, or atleast a central viewing area CVA of the other layers that overlie thecentral opening 42, must also be made of materials that allow visibilityinto the sealed container. Another beneficial feature is to provide aliner that allows an aroma from the product to pass through the centralopening 42 and the CVA of the other layers 20, 30 of the heat-sealliner. This again may be advantageous for sale or display purposes.Various materials to accomplish these purposes are described below.

As shown in FIGS. 3-4, and described below in one method embodiment formaking the liner 10, adhesive layers A may be provided between the toplayer 20 and the intermediate layer 40, and between the bottom layer 30and the intermediate layer 40, to enable adhesive lamination of allliner components to form an integral liner 10. In this embodiment, theadhesive A has flowed into the central opening 42 during lamination, tofill the opening with adhesive 42A; this may strengthen the overallliner structure. However, to maintain the CVA (central viewing areathrough all liner layers aligned within OD of central opening 42) theadhesive area 42A must also be of a see-through material (by see-throughit is meant that a person is able to perceive (detect) with a human eye,the interior contents P of the container). Similarly to allow for aromadetection by a human nose, the adhesive area 42A must provide for aromapenetration in the CVA. As noted previously, the adhesive layer(s) maybe included as part of (a component layer of) any one or more or the toplayer 20, intermediate layer 40, or bottom layer 30.

FIGS. 5A-5B are schematic views of one method embodiment for making aplurality of liners of the type shown in FIGS. 1-4, i.e., by laminatingtogether three component sheets that form the top, intermediate (metalfoil) and bottom layers of the liner respectively. FIG. 5A shows a holepunch 2 forming the central openings 42 in an intermediate (metal-foil)layer sheet (40-sheet), followed by the top 20-sheet, hole-punchedintermediate 30-sheet and bottom 30-sheet layer sheets) being sentthrough the nip of a pair of rotating rollers 4 for forming a laminatedcomposite sheet or web (10-sheet or 10-web). The laminated sheet-10 isthen wound on a large roller 5 (e.g., for storage/transport prior tosubsequent processing). FIG. 5B shows a subsequent hole punching stepfor forming a plurality of individual liners 10 by cutting completelythrough the thickness direction of the composite sheet 10-sheet (i.e.,hole punching to form the outer diameter LOD of each liner 10).Alternatively, the steps of FIGS. 5A and 5B can be combined into onesequential in-line process by eliminating the step of winding onto thelarge roller 5 prior to hole punching the individual liners.

FIG. 6 shows an alternative liner embodiment 110 (similar to FIGS. 1-4)that includes a further support layer 122 for structurally supportingthe metal-foil layer prior to, during and/or after assembly. The view ofFIG. 6 is similar to that of FIG. 1, showing the separate component(top, intermediate, bottom) layers of the liner in a spaced-apart,vertically-aligned position (in the thickness direction TD) between thecap 60 and container rim 82, with like layers of the liner bearingsimilar reference numbers but in a “100” numbering series. In thisembodiment the liner 110 includes in serial order from top to bottom: acontinuous uppermost layer 121, a support layer 122 having a centralopening 123 surrounded by a continuous peripheral area 124 (here thelayers 121 and 122 together comprising a top layer 120); an intermediatemetal-foil layer 140 having a central opening 142 and a surroundingcontinuous metal-foil peripheral area 144; and a bottom layer 130(including an upper layer 134 and a lower layer 131, the same as in theFIG. 1 embodiment). In various embodiments, the support layer 122 can beprovided above or below the metal-foil layer 140, and can be a componentof any of the top, intermediate or bottom layers as desired by aparticular application.

Providing the support layer 122 with a central opening 123 enablesbenefits both in the final (laminated) liner assembly 110, such aspreventing wrinkling or tearing of the metal-foil layer 140. It alsoprovides benefits during manufacture, e.g., in the process of FIG. 9A(described further below), starting with a sheet of a support layermaterial and a sheet of a metal-foil material in planar, face-to-faceengagement (together comprising the intermediate 240-sheet of FIG. 9A),the two sheets can be hole-punched at the same time by initial holepunch 202 forming central openings 123, 142, in both the support layer122 and metal-foil layer 140 simultaneously.

In one embodiment, a polymer film (forming support layer 122) can beapplied to one surface of a metal-foil sheet (forming metal-foil layer140) by an adhesive lamination process, e.g., use of a solvent adhesiveto bond the layers. The central openings 123, 142 in both the supportlayer 122 and the metal-foil layer 140 can be the same size as the riminner diameter RID, or can be less than RID (e.g., the size can beadjusted depending on the desired visibility through the liner, and/oraroma penetration through the liner, based on the various materialproperties and dimensions of the liner layers).

FIGS. 7-8 illustrate an alternative embodiment, referred to as a dualheat-seal liner, configured to be induction heat-sealed on its opposingtop and bottom faces to the cap interior top wall and the container rim(e.g., during the filling/capping step at the product filler) to form anon-removable closure assembly. Containers with a non-removable closure(cap/liner) assembly, are commonly used for food products such asketchup, mayonnaise, salad dressing and other products that can beconveniently packaged and dispensed through a dispensing aperture of asqueezable container assembly without removing the closure. In theembodiment of FIGS. 7-8, the dual-heat seal liner 210 includes at leastone central opening 212 extending in the thickness direction TD throughall component layers 220, 240, 230 so as to form a dispensing aperture212 extending through the entire thickness of the liner 210. This linercan be used with a cap 260, as shown in FIG. 8, also having a dispensingaperture 265, wherein the cap 260, liner 210 and container 280 togetherform the non-removable closure assembly configured to be used (by theconsumer) to dispense a product P held in the container body 286 withoutremoval of the cap 260 or of the induction heat-seal liner 210. The caphas a hinged closure lid 266, such as a flip top, for closing thedispensing aperture 265 when not in use (and to protect the product Pfrom spoilage). Typically the manufacturer does not want the containerto be re-filled, and thus the liner includes, in addition to theheat-seal bottom layer 230 for induction heat-seal bonding to thecontainer rim 282, a heat-seal top layer 220 for induction heat-sealbonding to the inner top wall 262 of the cap, rendering the capnon-removable from the combined (dual induction heat-seal bonded) cap,liner, and container assembly.

FIG. 9A shows one method of making the dual-seal liner 210 of FIGS. 7-8.A sequential in-line process is shown in which three layer sheets220-sheet, 240-sheet, and 230-sheet are provided for forming the top220, intermediate 240 and bottom 230 layers respectively. In thisembodiment, an initial hole punch 202 forms central openings 242 in theintermediate (metal-foil) sheet 240-sheet, the three sheets are then fedbetween a pair of rotating rollers 204 to laminate the sheets togetherto form a composite sheet or web 210-sheet, and then at least one commonliner ID hole punch 206 forms the liner inner diameter through all threesheet layers (to form the liner ID). Subsequently a further liner ODhole punch 208 is used to form the liner outer diameter LOD for aplurality of liners 210. In various embodiments, the outer diameter LODof liner 210 and the liner inner diameter LID (of central opening 212)can be made (e.g., punched) either simultaneously (e.g., by using asingle liner ID/OD hole punch 209 as shown in FIG. 9B with inner andouter cutting rings to form the inner and outer liner diameters of theannular liner), or sequentially (typically punching 212 first and 210second) as in FIG. 9A with hole punches 206, 208.

Also advantageous in this embodiment, the metal-foil layer 240 can havean initial central opening 242 that is larger (e.g., of greaterdiameter) than the common central opening 212 (liner ID), and thematerial(s) of the top and/or bottom layers 220, 230 (or adhesive Aforming part of those layers) is then allowed to flow into or otherwisefill the space defined by the initial central opening 242 (in themetal-foil layer 240), so as to fully or partially fill that space withadhesive 242A. The fully or partially filled space provides an area thatsurrounds the periphery of the central opening 212 in the metal-foillayer 240, in order to prevent the product P that is being dispensedthrough the common central opening 212, from reaching the metal-foilperipheral portion 244 of layer 240. This prevention (of product tometal-foil contact) will reduce the damaging effects of such contactwhich may include one or more of corrosion of the metal-foil layer,delamination of the liner layers, and/or a defective heat-seal bond withthe container rim or the inner top wall of the cap.

The liners described herein may be manufactured from various materialsand by various methods to achieve the aforementioned advantages.

As used herein the top, bottom and/or intermediate layers may be singlelayer or multi-layer embodiments, wherein one or more layers is providedas a coating layer, and/or one or more layers are continuous or lessthan continuous across the liner area (in a direction transverse to thethickness direction).

In various embodiments, the top, bottom and/or intermediate layers mayinclude one or more polymer materials, such as polyolefins (e.g.,polypropylene (PP) or polyethylene (PE) based polymers), polyesters(e.g., polyethylene terephthalate (PET) based polymers), polyamides(e.g., nylon based polymers), including copolymers, and blends thereof.Furthermore, one or more paper layers may be present.

In various embodiments, the metal-foil layer may be formed of one ormore of metals, such as aluminum (Al), tin, copper or steel.

The liner may be formed by any one of various lamination methods,including adhesive lamination, extrusion lamination or thermallamination (without adhesives). For adhesive lamination, the adhesivelayers may comprise one or more of the top, bottom or intermediatelayers, adjacent to the intermediate metal-foil layer, and/or betweenother layers of a multi-layer structure. The adhesive (glue) can beapplied to the top or bottom layers, e.g., a PET heat seal layer, or toa polypropylene layer. It may be less preferred (e.g., more difficult)to apply adhesive to the metal-foil layer because of the centralopening.

The induction heat-seal bonding material may be included in the topand/or bottom layers as a surface layer, e.g., as a solvent coating to abase film (e.g., DuPont Teijin Mylar CL Polyester Film), as an extrusioncoating to a base film (e.g., as a hot melt adhesive), or as a distinctlayer. The induction heat-seal bonding materials may comprise one ormore polymer materials that bond in a temperature range of from 60 to210 degrees Celsius. Representative materials include polyolefin,polyester and nylon materials. Typically the heat-seal material is acontinuous layer across the entire liner area (transverse to thethickness direction TD); however it can be a partial layer that isapplied only to the liner periphery where needed to bond to thecontainer rim (i.e., a continuous peripheral area around the peripheryof the liner).

The material used for the cap and container will depend upon theparticular application. In one embodiment, the cap is made ofpolypropylene (PP), and the container is made from polyethyleneterephthalate (PET), polypropylene (PP) or polyethylene (PE). Thecontainer may be made from an injection molded preform, the body portionof which is blow molded to form the container body. The rim may have anOD in a range of 28-89 mm, and a wall thickness in a range of 0.045 to0.110 inch. For the non-removable closure embodiment, the dual heat-sealbonded cap, liner and container assembly can preferably withstand atorque or at least 50 inch-pounds, and more preferably 70 inch-pounds,without loss of the dual heat-seal bonds or distortion of the cap orcontainer.

In one adhesive lamination method embodiment, the three component layers(top, intermediate, bottom) of the liner can be laminated in one step,by first applying adhesive to the top and bottom layers and sending allthree layers (with the hole-punched metal-foil intermediate layer in themiddle) through a nip of a pair of rotating rollers as shown in FIG. 5Aor 9A. Alternatively, a sequential process can be used to join thelayers.

In one heat lamination method embodiment, a support film of PET/EAA canbe used (e.g., Dow Primacor Ethylene Acrylic Acid) that adheres well toAl foil to form the intermediate layer. All three layers (top andbottom, with the intermediate layer in between) are then sent through anip of a pair of rotating rollers as shown in FIG. 5A or 9A, whileapplying heat and pressure to form the integral liner.

The shape of the container rim, and complementary liner shape, is notrequired to be disc (circular) or annular (ring-shaped). Other rimshapes can be utilized, including any multi-sided shape with straight orcurved sides, having sharp or rounded junctions between the sides.Another embodiment shown in FIGS. 10A-10B, similar to the FIGS. 1-4embodiment. The FIG. 10A embodiment includes a cap 360, liner 310, andcontainer 380 assembly where the container rim 382 and the liner 310 aregenerally rectangular in shape (in cross section transverse to thethickness direction TD), with two opposing relatively straight right andleft outer side edges 393A and 393B, two opposing outwardly-bowed frontand rear outer side edges 394A and 394B, and rounded corners 395 therebetween. The liner includes a pull tab 314 as previously mentioned toassist in removing (pulling) the liner 310 off of the container rim 382to access the product P held in the container body 386. The container380 is designed to hold an aromatic product, and the scent of theproduct (held in the container body) can be detected (by a human nose)through a CVA of the liner (defined by inner edge 3401E of theintermediate metal-foil layer 340). Here the CVA may allow just aromadetection, or alternatively can allow both visual detection and aromadetection of the product in the container (through the CVA of theliner), or just visual detection. FIG. 10B shows the metal-foilintermediate layer 340, having a central opening 342 surrounded by aperipheral metal-foil area 344, the latter for activating heating of theheat-seal bonding material 330 for bonding to the container rim 382.

There are multiple applications where visual detection, and/or aromadetection, would be of great value to the consumer, and where thecontainer must also provide protection against leakage, spoilage orcontamination of the product and thus requiring use of a heat-sealliner. Products that would benefit from visual and/or aroma detection,without removal of the heat-seal liner, include products such as foods,beverages, cosmetics, confectionery, household products, air care andother items in the form of creams, gels, powders, liquids or solids, soas to permit the scent or aroma of the product to be released though theseal (or visual observation of the product) without providing directaccess to the product.

These and other alternative embodiments are intended to fall within thescope of the pending claims.

1. An induction heat-seal liner comprising: a top closure-facing layer,a bottom heat-seal bonding layer, and an intermediate metal-foil layerdisposed in a thickness direction between the top and bottom layers, thetop, bottom and intermediate layers being bonded to form an integralinduction heat-seal liner, the metal-foil layer having a central openingsurrounded by a metal-foil portion configured to lie above a containerrim surrounding an open mouth of a container body, and the bottom layerhaving a heat-seal bonding area configured to lie above the containerrim that is activated by heating of the metal-foil portion to inductionheat-seal the bonding area to the container rim.
 2. The liner of claim1, wherein the liner having a central portion, aligned in the thicknessdirection with the central opening of the metal-foil layer, comprisingone or more materials or spaces that provide visibility into and/oraroma penetration from the open mouth of the container, allowing visibledetection of and/or aroma detection of a product in the container body.3. The liner of claim 1 wherein: one or both of the top and bottomlayers fills or partially fills the central opening of the metal-foillayer.
 4. The liner of claim 1 wherein: the integral liner comprises anadhesive, extrusion or thermally laminated body.
 5. The liner of claim 4wherein: the liner is an adhesive laminated body and includes adhesivebetween one or more of the top, intermediate and bottom layers, and theadhesive fills or partially fills the central opening of the metal-foillayer.
 6. The liner of claim 2 wherein: the central liner portion isclear or translucent to permit visible detection of the product in thecontainer body.
 7. A method of forming the liner of claim 1 comprising:a) providing the metal-foil layer having the central opening; andsubsequently b) laminating the metal-foil layer between the top andbottom layers to form the integral liner.
 8. The method of claim 7wherein: the laminating step comprises adhesive laminating themetal-foil layer between the top and bottom layers.
 9. The method ofclaim 8 wherein: during the laminating step adhesive layers fills orpartially fills the central opening of the metal-foil layer.
 10. Themethod of claim 7 wherein: the providing step includes providing asupport layer having a central opening, and the laminating step includesdisposing the metal-foil layer and the support layer with their centralopenings aligned between the top and bottom layers to form the integralliner.
 11. The method of claim 10 wherein: the providing step includesproviding a sheet comprising the metal-foil layer and a sheet comprisingthe support layer, and forming the central openings through both sheetssimultaneously.
 12. A method of forming the liner of claim 4 comprising:a) providing top, intermediate and bottom sheets for forming the top,intermediate and bottom layers respectively; b) laminating the sheetstogether to form a laminated composite sheet with the intermediate sheetlaminated between the top and bottom sheets; and c) forming individualliners from the laminated composite sheet by cutting through thecomposite sheet in a thickness direction.
 13. The method of claim 12wherein the central opening in the metal foil layer is formed prior tothe laminating step.
 14. The method of claim 13 wherein during thelaminating step the central opening is wholly or partially filled in.15. The method of claim 13 wherein the method is a sequential in-linemethod including steps of: prior to the laminating step, forming thecentral openings for a plurality of liners in the intermediate sheet;the laminating step comprises feeding the sheets through one or moreroller pairs for laminating the sheets together to from the laminatedcomposite sheet; the forming step comprises cutting through thelaminated composite sheet in the thickness direction to form theplurality of liners.
 16. The method of claim 15 wherein the steps offorming the central openings and cutting to form the individual linerseach comprise hole punching.
 17. The method of claim 12 wherein thecentral opening and individual liner are formed simultaneously. 18-34.(canceled)